Triple Threat

Admin · March 3, 2022

MV Agusta chief project engineer Dr. Brian Gillen standing next to his latest creation in the dyno room for its final power and homologation runs. The 950 features three catalytic converters and will be certified as Euro 5 compliant. (Bruno dePrato/)

MV Agusta’s 675/800cc triple is an engine of many talents. In terms of tractability, maximum power, and reliability, the three-cylinder is one of the most attractive engines in its class. Its solid qualities have been confirmed in competition, with good results in the Supersport World Championship series (WorldSSP), where it battled bravely against the Japanese fours. That it missed winning the overall title was largely due not to any faults, but to the team’s limited budget.

Although also available as a 675, for most riders the 800cc version is the most interesting, as it offers an attractive combination of lightness, compactness, and high-performance potential.

The modern MV three first came to life in 2012, but the market has undergone significant change since then. Today more than ever, price is a determining factor, but value means different things to different riders. Still, an engine in this class must offer a competitive ratio of performance to cost, and much of MV’s engine changes address just that.

Related: MV Agusta’s Game Plan for 2022

Overcoming Problems

The earlier generation of the triple was excessively complex, which drove costs up and profitability down. MV’s various attempts to address this came up short, and the only realistic solution was to go back to the drawing board and make the whole engine easier and less expensive to manufacture while retaining its virtues: compactness, light weight, and performance.

MV even explored supercharging, but in the end everything pointed to trying to extract the largest possible displacement from a moderately renewed block, while at the same time eliminating the problems of inefficient tooling and overcomplicated machining. The task fell to CPE Gillen and his team. It was both huge in itself and critical for MV Agusta’s future, since this next-generation three was regarded as pivotal both for any new models and for the brand’s image.

The final result has been a resounding success: In the new Lucky Explorer 950 adventure-tourer, the 930.6cc transverse triple delivers 123 hp at 10,000 rpm and 75.2 pound-feet of peak torque at 7,000 rpm, all while meeting or exceeding Euro 5 emissions requirements.

MV pushed the bore from 79mm to 81mm while keeping the center-to-center spacing unaltered. The short-stroke (60.2mm) design is oversquare and can be safely revved to 12,000-plus rpm “in case of need.”

Compactness as a Virtue

The 950 engine has grown only 10.7mm taller, measured vertically from the center of the crankshaft. Since the cylinder block is inclined markedly forward, it also grew 7mm measured horizontally from the same reference point. That the block grew taller is far more acceptable, in terms of development and tooling costs, than if it had grown wider; a wider bore spacing would have generated a higher primary-order imbalance.

But the ultimate benefit is that the new 950 can use the head from the 800 triple, dramatically slashing the development and tooling costs. Other updates include a new clutch that helped reduce overall width, and oil and cooling fluid lines routed outside the crankcase to eliminate one of the headaches of the previous design.

Let’s take a look at some of the engine’s details:

The cylinder block is a closed-deck design. The 81mm pistons have a clean top with large squish areas and a 12.5:1 compression ratio. Cylinder block, crankcase, and head are all gravity sand cast. New dies ensure superior quality and structural consistency. (Bruno dePrato/)
The new crankshaft not only provides a longer 60.2mm stroke, but is also stronger, with four 37mm main journals and three 35mm rod journals. The integral gear drives the balancing shaft at 1:1 to cancel the vibrations generated by the primary-order rocking momentum typical of an inline-three. (Bruno dePrato/)
A nozzle spraying a jet of cooling oil to the underside of each piston is located at the bottom of each cylinder bore. (Bruno dePrato/)
At 81mm, the 950’s cylinder bores are 2mm larger than the 800’s. To make them fit and keep the engine narrow, the cylinder barrels are integral to the aluminum block, Nikasil plated, and use a siamesed design. Center-to-center bore spacing remains unchanged, a fundamental factor in keeping the new engine and its tooling costs competitively priced. (Bruno dePrato/)
Pistons are a two-ring-plus-oil-scraper design, very light and featuring very compact skirts. The piston crowns feature large and well-contoured squish areas and a very clean, slightly dished profile for optimal flame travel and combustion. (Bruno dePrato/)
Connecting rods are totally new in both design and size. Even though they are 10mm longer to maintain the correct stroke-to-con-rod-length ratio, they’re still very light. (Bruno dePrato/)
The oil-cooler pump is new, compact, and immensely more functional than the previous unit. (Bruno dePrato/)
The six-speed gearbox is all new and both stronger and smoother. Straight-cut advanced-module gears are expected to be quieter and absorb less power than Gleason-type helical-cut gears. (Bruno dePrato/)
The 950’s head features a shallow combustion-chamber profile, with valves set at 23 degrees (included) angle for a 12.5:1 compression ratio. Intake valves measure 31.8mm, exhausts 26.7mm. (Bruno de Prato/)